Abstract
The effect of metallurgical factors (e. g. weld microstructure) on the failure mode of resistance spot welds is studied. In the light of failure mechanism of the spot welds, a simple analytical model is proposed to estimate minimum fusion zone size to ensure pull out failure mode of resistance spot welds during tensile-shear test. According to this model, ratio of fusion zone hardness to pullout failure location hardness and volume fraction of porosity in the fusion zone are the key metallurgical factors governing failure mode of spot welds during tensile-shear test, in addition to sheet thickness. Finally, the proposed model is compared with experimental results.

Key words
resistance spot welding, failure mode, fusion zone size

Full text (310 KB)